Babitting Session - SCMAFC

On the evening of Tuesday, April 18, Gord Watt invited our club to see him do the babbitting of Yvan Picot’s engine block. Gord has been doing this for the APAC for many years, in a garage that they have rented since 1974. Incidentally, they were given notice to vacate this summer, and are currently looking for another garage to rent. If you know of any space they can use, I’m sure that Gord would appreciate hearing from you.

We had an excellent turnout. 15 members showed up, which is about all that the garage could handle. Paul Chudek had the distinction of bringing the first model A to this year’s events. We met at Westbrook Hotel and then headed to the garage.

Yvan’s engine block had all the machining done, except of course for the main bearings. Gord had previously turned on the flame for the melting pots. There are two, one for the tinning solder and one for the babbitt. He keeps the solder at 500 degrees F, and the babbitt at 700 degrees.

The equipment which Gord uses was purchased from the local Federal Mogul agency in 1970, when they got out of engine babbitting. They have all the melting pots, mandrels and jigs for any old car or even tractor. This equipment is irreplaceable, and certainly makes the job a lot easier.

Gord likes to do the block first, as it is the hardest part of the job. He had Yvan clean up the bearing seats with a wire brush, so that they were shiny. He then stuffed the oil tubes with a fire proof material that keeps the babbitt from running into them. There are may different philosophies on babbitting techniques, and Gord has come up with a system that works well. He heats up the block with a tiger torch to about 700 degrees. Some people in the U.S. like to do it cold. Gord has found that heating it up makes the babbitt stick better, and eliminates the chance of any moisture on the bearing seat. Moisture can cause the molten babbitt to spit back out. He didn’t tin the block, because it’s too big, and there are holes drilled in the journals to hold the babbitt.

He placed the mandrel onto the block, which has dowels that locate it into the bearing bolt holes. The mandrel is a steel bar with disks which fit snugly against the end of the bearing seats. This acts as a mold around the bearing seat to hold the babbitt. Gord then poured the babbitt into each of the three bearings. He makes it look easy, but it has taken years to know how to do it without getting voids in the babbitt. He uses a large cast iron ladle to pour.

There are two types of babbitt available. Gord buys it in ingots from Canada Metal. He prefers to use what is called Harris heavy pressure babbitt, which has a lead base. There is also a type called nickel genuine, which actually has no nickel at all. It is a harder material and has a tin base.

The bearing caps were done next. He heated up the rear main cap to burn out any gunk in the oil drain passage. He cleaned up the caps with a wire brush and then dunked them into the solder pot. They were then dipped into a pail of zinc chloride acid. The acid etches the solder so that the babbitt will stick to it. This is called "tinning" the caps. It took a few tries to get each one properly tinned. When there are rough looking spots in the solder, it means that there isn’t enough on, so he dunked them again until they were properly covered. He had two special jigs already set up. One was for the front and center caps, and the other was for the rear main. These jigs hold the caps, and act as a mold for pouring. Gord installed the caps one at a time and then heated them, jigs and all, with his tiger torch. He used a special heat chalk to measure the temperature of the workpiece. It changes colour when it is 700 degrees. He then quickly and carefully poured the babbitt and checked the results after cooling. A couple of times the jigs leaked, causing a rough spot or possibly a void in the babbitt. He doesn’t take chances when that happens, so he simply dropped the cap back into the babbitt pot to melt it off and tried again. The whole process didn’t take very long, about 2 hours. Gord had previously done Yvan’s connecting rods.

Thanks again Gord for showing us this process, which is quickly becoming a dying art. Incidentally, modern engines still use babbitt as bearing material, because nothing better has ever been found. The difference is that it is applied as a thin film onto steel shells which bolt into the engine, rather than by the old pouring process.